Internal-combustion engine of the two-cycle type.



S. B. D. HARDING.

I INTERNAL COMBUSTION ENGINE OF'THE TWO-CYCLE TY E.

Patel lted Feb. 8, 1916.

APPLICATION FILED FEB. 6, I914.

Witnesses INTERNAL-COMBUSTION ENGINE OF THE TWO-CYCLE TYPE.

Specification of Letters Patent.

Patented Feb, a, rare.

Application filed February 6, 1914. Serial No. 816,982. a

To all whom it may concern:

Be it known that I, SHERREN BRUCE DOUGLAS HARDING, a subject of the King of Great Britain, residing at Wyhitecross I. street, London, England, have invented new and useful Improvements in internal-Combustion Engines of the Two-Cycle Type, of which the following is a specification.

'ihis invention relates to internal combustion engines of the single-acting two-cycle type, and has for its object the obtainment of an air scavenge and the avoidance of crank-chamber compression whereby a higher compression pressure-without curtailing the scavenge of the working cylin-. deris obtained, and the efiiciency of thls type of engine thereby materially increased. 1 attain this end by the employment of a piston having a tubular trunk to which the connecting rod is directly coupled and whlch operates as a slide valve for controlling the admission of air for scavenging purposes, and by compressing and firing the charge 1n the forward part of the cylinder, 2'. e. the

' part in advance of the piston so that during the working stroke the piston is moving away from the crank-shaft.

In the accompanying drawing which illustrates this invention the figure 1s a new in elevation, partly in section, showing the piston at the end of its firing or working stroke.

The piston a, which works in the, cylinder b, is open at its upper end and carries a tubular trunk 0 on its lower end, said trunk being closed at 01' near its free end and in communication with the interior of the piston at its connection therewith. The free end of the trunk 0 is coupled by a connecting rod d with the crank-shaft e mounted in a I crank-case or chamber f in the usual manner:

The cylinder b, which is inverted and is mounted at a suitable distance'above the crank-chamber has an exhaust port it, at or about the center of its length which is opened-and closed by the piston a at or about the end of its working stroke. In the cylinder is also an inlet port Z which is adapted to be opened and closed by the piston a at or about the end of its compression stroke. In the hollow rod or trunk 0 above the diaphragm which closes its lower end, is a series of ports m which, when the piston reaches the end of its working stroke, coin cide with a series of ports a in an internal sleeve 6 projecting upward from the bottom of the working cylinder 6 and which,

when the piston is at the end of its compression stroke, coincide with a series of .ports p in a cylindrical extension p of the cylinder b, which serves both as a distance piece between the cylinder and the crank-chamber and as a guide for the rod or trunk of the piston. As the ports m register with the ports 79 at the same time that the ports Z are uncovered by the piston, air and gas are admitted into the trunk of the piston and into the back end of the cylinder respectively simultaneously. The ports p, which are open to the atmosphere, are provided with any suitable device such as a rotating perforated band 1', as shown in the accompanying drawing, for the purpose of varying the area of the ports 1) and so controlling theamount of air admitted to the engine. The bottom end of ,the cylinder b is provided with any suitable device for igniting the charge.

The cycle of operations is as follo.ws-:-As the piston travels downward on its compression stroke a negative pressure or slight vacuum is created in the top or back end of the cylinder 1) so that when the piston reaches the end of its compression stroke and the inlet ports Z are uncovered by the piston a and the ports on are brought into register with the air ports p, gaseous mixture flows in through the ports Z and air through the ports 9 whereby the back end of the cylinder, the piston and the hollow rod or trunk become charged with the gaseous mixture and airin a Stratified condition, the mixture being on the top of the air. At this time the charge in the annular working space of the cylinder is fired and ,the working stroke commences, when as soon as the portsl and p are closed the gaseous mixture and the air (in a stratified condition) are compressed. v When the piston approaches the end of its working stroke the exhaust port it is opened and the ports m coincide with the ports a whereupon the air followed by the gaseous mixture rushes out through the ports m and a into the annular working space ofthe cylinder, the air scavenging said cylinder and the gaseous mixture charging same, thegmovement of the pistonon its forward or down stroke being timed to close the exhaust port It immediately the scavenging air has passed out of said port and the gaseous mixture has filled the cylinder.

It will be seen that in this engine crankchamber compression is done away with so that a greater compression pressure can be trunk of the piston, inlet ports in the cyl inder adapted to be opened to the back or upper end of the cylinder as the piston reaches the end of its downward or nonworking stroke, exhaust ports in the cylinder adapted to be opened by the piston as it reaches the end of its upward or working stroke, an internal sleeve in the bottom or forward end of the cylinder through which the trunk of the piston works, ports in said internal sleeve with which the ports in the trunk of the piston register when the piston approaches the end of its upward or working stroke, a crank chamber supporting a crank shaft, a couple between said crank shaft and the tubular extension of the piston, a sleeve extension of the cylinder which forms both a guide for the trunk of the piston and a distance piece between the cylinder and the crank chamber, and ports in said sleeve extension adapted when the piston is at the mmeoo end of its downward or non-working stroke to coincide with the ports in the trunk of the piston, as set forth.

2. A single acting internal combustion en gine of the two-cycle type comprisinga cylinder, an annular piston Workingin said cylinder, a trunk carried by said piston and closed at its free end, ports in the free end of said trunk, ports in the cylinder adapted to be opened to the back end of the cylinder as the piston reaches the end of its non-working stroke, exhaust ports in the cylinder adapted to be opened by the piston as it reaches the end of its working stroke, a crank chamber, a crank shaft mounted in said chamber, a connecting rod coupling said crank shaft with the trunk of the piston, a sleeve extension of the cylinder extending upward into said cylinder and downward to be fixed'to the crank-chamber, ports in said sleeve within the cylinder adapted to be uncovered by the trunk of the piston as the piston approaches the end of its working stroke, and ports in the sleeve extension of the cylinder adapted when the piston is at the end of its non-working stroke to coincide with the ports in the trunk of the 1 piston, as set forth.

Signed at London this 27 day of January 1914.

SHERREN BRUCE DOUGLAS HARDING. 

